This Part Fits the following kits / parts:

#108727 - HEAVY-DUTY PINION GEAR 14T (8mm BORE/1.5M)

Baja 5B FLUX

Fine-tune the speed and acceleration of the Baja 5B Flux with a selection of
Heavy-Duty pinion gears. Use a larger pinion gear for higher top
speeds, or use a smaller pinion gear for increased acceleration.